Technical paper: Ultrahigh-density silicon nanobridges formed between two vertical surfaces

Scientists at HP Labs have
devised a method of growing and connecting semiconductor nanowires
in place, which could eventually lead the way to more effective sensors
for detecting toxic gases and other chemical or biological substances.

In a paper in the accelerated Web version of the journal Nanotechnology (Vol. 15, No. 5) the
scientists describe how they formed silicon nanowires between
vertical silicon "walls." The wires start growing from one wall, extend across the space between walls, then attach firmly to the other wall to form strong mechanical connections.

The scientists -- Saif Islam, Shashank Sharma, Ted Kamins and
Stan Williams -- say that by using large numbers of these "nanobridges" in
parallel, they were able to obtain the high surface-to-volume ratio
needed for sensors. Other potential applications include interconnecting "leads" in
nanometer-scale electronic circuits and devices within nanowires
(transistors, for example). This technology also provides a platform for molecular electronic devices.

In their paper, the researchers argue that HP Labs’ approach
has several advantages over competing ones that have relied on carbon
rather than silicon. Nanowires formed from silicon are more versatile
and controllable than carbon nanotubes, and they are more easily
integrated into conventional integrated-circuit processes.

The paper’s authors are all members of HP Labs’ widely
recognized Quantum Science Research (QSR) group. In related work,
QSR has achieved important results and been granted key patents in
techniques that could make practical the fabrication of molecular-scale
electronic devices.

Nanotechnology, published by the Institute of Physics
Publishing, is the first journal dedicated to coverage of all aspects
of nanoscale science and technology from a multidisciplinary perspective.